TiO2-coated glass hollow fiber membranes: preparation and application for photocatalytic methylene blue removal

A glass hollow fiber membrane coated with TiO₂ was successfully synthesized by dip-coating and calcination. In addition, the effects of the calcination temperature, number of coating layers, and treatment method on the photocatalytic removal of methylene blue from wastewater by the membrane were investigated. The results showed that the TiO₂-coated membrane calcined at 550 °C was uniform. It showed good photocatalytic and anti-fouling properties. As compared to the basement membrane, the TiO₂-coated membrane showed significantly improved photocatalytic removal of methylene blue. It showed a methylene blue removal degree as high as 97.2% and could be recycled multiple times by a simple treatment. The methylene blue removal degree of the membrane remained 92.3-93.6% after five recycling operations. Therefore, the membrane prepared via the simple method proposed in this study could be used as an efficient photocatalyst to remove methylene blue from wastewater.     

Adsorption and photocatalytic decomposition of methylene blue on mesoporous metallosilicates

Mesoporous silica and mesoporous metallosilicates with Al, Ti and Fe as foreign metal species were successfully synthesized by the rapid room temperature method. Mesoporous metallosilicates with low contents of foreign metals possessed high surface area (S_a), large mesopore volume (V_mp) and highly ordered hexagonal mesoporous structure. Increases in foreign metal contents caused disordering the mesoporous structures and lowering the S_a and V_mp values. Bleaching of aqueous methylene blue (MB) by mesoporous silica and metallosilicates was investigated. Mesoporous aluminosilicate and ferrosilicate with cation-exchangeable ability showed the excellent property for the adsorption of MB of cationic dye, while mesoporous ferrosilicate and titanosilicate which absorbed UV lights catalyzed the photocatalytic decomposition of MB under UV-illumination.     

纳米WO_3的制备及光催化降解亚甲基蓝的研究

以钨酸钠和盐酸为原料,采用水热法制备纳米WO_3,并利用X射线衍射分析(XRD)、X光电子能谱分析(XPS)、扫描电镜(SEM)和热重分析(TG-DSC)等手段进行表征。结果表明,焙烧温度对WO_3的晶型会产生影响,焙烧温度控制在600℃可获得单斜相的WO_3。另外,考察了纳米WO_3在紫外光照射下光催化降解亚甲基蓝溶液的催化性能,结果表明,溶液初始溶度6 mg/L,初始pH=11,WO_3用量为0.2 g/100 m L,在300 W汞灯光照条件下反应2 h时,亚甲基蓝降解率为93.7%。     

Ca系永磁铁氧体工艺与磁性研究

用陶瓷工艺制备了Ca系永磁铁氧体,用X射线衍射仪分析样品的物相,用振动样品磁强计、永磁铁氧体测量仪、浮力法等对产品相关磁特性进行了检测,用扫描电子显微镜(SEM)观察样品的断面形貌。实验表明,微量Ba的掺杂促进了Ca系铁氧体片状晶粒的均匀生长,磁性能得到明显改善,矩形比(Hk/HCJ)从89%提高到96%,M*值提高2.6%,达到6 200以上,对Ca_(0.98-x)La_xBa_(0.02)Fe_(10.6-x)Co_xO_(19)(x=0.3),1 300℃保温1 h的预烧料粉碎时添加0.2%的H_3BO_3、0.4%的Si O_2,研磨之后成型,成型坯适当低温长时间的烧结更有利于Ca系永磁铁氧体磁参数的改善,如将其烧结温度控制为1 195℃并保温2 h,可获得B_r为452 m T,H_(CJ)为402 k A/m的Ca永磁铁氧体。     

MnO_2纳米颗粒的制备及其对亚甲基蓝的吸附性能

采用一步氧化还原法室温制备了Mn O2纳米颗粒,并考察了其对亚甲基蓝的吸附性能。结果表明,制备的Mn O2纳米颗粒大小均一,为无定型的δ-Mn O2,其对亚甲基蓝具有较好的吸附性能,最大吸附量可达157.7 mg/g,且吸附过程符合Langmuir等温模型和准二级动力学方程。     

MnO_2纳米颗粒的制备及其对亚甲基蓝的吸附性能

采用一步氧化还原法室温制备了Mn O2纳米颗粒,并考察了其对亚甲基蓝的吸附性能。结果表明,制备的Mn O2纳米颗粒大小均一,为无定型的δ-Mn O2,其对亚甲基蓝具有较好的吸附性能,最大吸附量可达157.7 mg/g,且吸附过程符合Langmuir等温模型和准二级动力学方程。     

Preparation of aerochitin‐TiO2 composite for efficient photocatalytic degradation of methylene blue

An aerochitin–titania (TiO₂) composite was successfully synthesized and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, and N₂ adsorption isotherms. The photocatalytic activity of the composite was investigated on the degradation of the model organic pollutant, methylene blue (MB) dye, under UV irradiation. The aerochitin–TiO₂ composite showed excellent adsorptive and photocatalytic activity with a degradation degree of 98% for MB. The first‐order rate constants for the photodegradation MB by TiO₂ nanoparticles and aerochitin–TiO₂ composite were found to be (3.49 ± 0.04) × 10^?3 and (1.82 ± 0.02) × 10^?2 min^?1. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45908.     

TiO2 纳米薄膜微结构及光催化性能研究

以钛酸丁酯Ti(OBu)4为原料,采用溶胶-凝胶法在普通钠钙玻璃表面制备了TiO2纳米薄膜,用XRD、UV-VIS等技术对薄膜微结构及紫外吸收性能进行了表征,选用食用油光催化降解为模型对TiO2薄膜光催化性能进行了评价。探讨了退火温度对薄膜晶相结构及其光催化活性的影响,450℃退火处理的薄膜呈锐钛矿和金红石型混晶结构,锐钛矿相平均晶粒尺寸为28.8 nm,金红石相平均晶粒尺寸为40.4 nm,700℃退火后为纯金红石相。焙烧温度在450—490℃光催化活性较为理想,480℃附近光催化活性达到最高。涂膜层数增加,光催化活性增强,8层膜的光催化活性最高。     

玻璃镀膜二氧化钛制备及降解亚甲基蓝研究

用溶胶-凝胶法在普通玻璃基体上制备了多层纳米二氧化钛薄膜,并用它来光催化降解有机染料亚甲基蓝。研究了镀膜层数、焙烧温度、通入空气和底物浓度对光催化降解率的影响。发现最佳镀膜层数为5层,最佳焙烧温度为550℃时,经TEM透射电镜观察,发现此温度焙烧的二氧化钛是处于催化效率最高的锐钛矿和金红石矿的混合相,降解10 mL浓度为5 mg/L的亚甲基蓝1 h的脱色率达78%。重复使用3次后脱色率基本不变,延长光催化时间,脱色率可以提高。     

超声制纳米TiO2及光催化降解活性深蓝的研究

介绍了TiCl4超声水解制备纳米TiO2的方法,探讨了超声波的作用机理,并以活性深蓝ST-2GLN为目标降解物,考察超声波及煅烧温度对纳米TiO2光催化性能的影响。结果表明:超声波能大幅度提高纳米TiO2光催化性能;300℃煅烧得到的纳米TiO2在催化剂质量浓度1.0g/L,25℃,8W紫外灯(波长254nm)照射,活性深蓝ST-2GLN水溶液初始质量浓度30mg/L的条件下,80min降解率即可达到99.7%。     

小沙粒/TiO2的制备及其光催化降解亚甲基蓝性能的研究

为避免粉状光催化剂的团聚和流失,提高其回收率,通过溶胶-凝胶法+焙烧法制备小沙粒/TiO2光催化剂.通过SEM和XRD等对材料的形貌和晶型进行分析和测试,并用亚甲基蓝降解实验考察其光催化活性.结果表明,TiO2质量分数12％时,光催化效果最好.紫外光作用20 min时,亚甲基蓝降解率达98.77％.制备的光催化剂具有良...     

开口空心ZnS/CdS纳米微球的制备、表征及其光降解亚甲基蓝性能

采用非均相回流技术制备开口空心ZnS/CdS纳米微球,利用TEM和XRD对样品进行表征与分析,通过降解亚甲基蓝溶液和正交设计试验考察各影响因素。结果表明,催化剂用量是影响光降解亚甲基蓝的主要因素,在催化剂用量70 mg、m(ZnS)∶m(CdS)=1∶3和避光搅拌时间30 min条件下,浓度10 mg·L^-1的亚甲基蓝溶液降解率达91.34%。     

Improved photocatalytic performance of Gd and Nd co-doped ZnO nanorods for the degradation of methylene blue

This paper reports the synthesis of pure ZnO, Gd and Nd co-doped ZnO nanorods based nanocomposites via simple hydrothermal method. Subsequently, the prepared photocatalysts were characterized using XRD, SEM/EDX, TEM, UV–visible and PL spectroscopy. The XRD results demonstrate that Gd and Nd ions were incorporated into ZnO lattice in the synthesized ZnO based nanocomposites and showed hexagonal wurtzite structure. The SEM and TEM results show that nanorods having nanoscale diameter and length were successfully synthesized by hydrothermal method. The UV–visible spectroscopy verified that the band gap of ZnO was reduced due to incorporation of Gd and Nd into ZnO photocatalyst. Similarly, Gd and Nd incorporation into ZnO was found effective to reduce the recombination of electrons and holes as confirmed by PL spectroscopy. Moreover, the prepared nanocomposites with various atomic ratios (0.5–2%) were tested for photocatalytic degradation of methylene blue (MB), under visible light irradiation. The highly efficient and optimized 1.5% Nd/ZnO nanocomposite demonstrated enhanced photocatalytic performance for the degradation of methylene blue compared to pure ZnO and other nanocomposites. Furthermore, the recycling results show that the 1.5% Nd/ZnO nanocomposites displayed good stability and long-term durability. These finding suggest that the ZnO based nanocomposite could be efficiently used in various energy and environmental applications.     

A novel nano-sized MoS2 decorated Bi2O3 heterojunction with enhanced photocatalytic performance for methylene blue and tetracycline degradation

In this paper, MoS₂ was used as a band-suitable semiconductor to construct the Bi₂O₃/MoS₂ heterostructured photocatalysts for the first time via a deposition-hydrothermal method. The XRD, SEM and HRTEM analysis indicated that the surface of Bi₂O₃ was decorated with MoS₂ nanoparticles and Bi₂O₃/MoS₂ heterojunctions were formed. The performances on photocatalytic degradation of methylene blue (MB) and tetracycline (TC) were evaluated under visible light irradiation. The results demonstrated that the Bi₂O₃/MoS₂ heterojunctions displayed remarkably improved photocatalytic activity for both MB and TC degradation, compared to the base material (Bi₂O₃). Specifically, as the molar ratio of MoS₂ was 23.81%, the obtained Bi₂O₃/MoS₂-23.81 heterojunctions exhibited promising photocatalytic activities, and approximately 100% MB and 97% TC were degraded within 100 min, respectively. The superior photocatalytic activity was mainly attributed to its large surface area, high visible-light harvesting and the efficient separation of photogenerated electrons and holes caused by the unique heterojunction architecture. Notably, the Bi₂O₃/MoS₂ heterojunctions showed remarkable stability in recycling photocatatlytic experiments. The active species trapping and terephthalic acid (TA) fluorescence experiments indicated that the •OH was the major reactive oxidizing species for MB degradation. Furthermore, the intermediates were detected by UPLC-MS spectrometry and the possible degradation pathways for MB and TC were proposed. Finally, a possible reaction mechanism of Bi₂O₃/MoS₂ heterojunctions for the photodegradation MB was also proposed. This interesting interfacial architecture strategy will provide useful insights for designing and fabricating new class of binary heterojunctions with high-efficient photocatalytic activity towards practical application.     

稀土掺杂纳米TiO2光催化剂制备及其光催化性能

采用溶胶-微波法制备掺杂不同稀土元素纳米TiO2光催化剂,借助XRD和UV-Vis吸收光谱等手段对其进行表征.以甲基橙为模拟污染物,考察样品的光催化性能.结果表明,适量的La3+、Nd3+、Eu3+、Gd3+和Y3+掺杂可提高TiO2样品的光催化活性,最佳掺杂物质的量分数分别为0.1%、0.1%、0.3%、0.2%和0...     

锰掺杂纳米二氧化钛的制备及其可见光催化性能

分别以MnSO4.H2O和MnC2O4.4H2O为锰源,采用水热法制备了锰掺杂的Mn-TiO2光催化剂,并采用X射线衍射、紫外-可见光漫反射光谱等技术对样品进行了表征。以罗丹明B的光催化降解为模型反应,考察了不同锰源、锰掺杂量对催化剂光催化性能的影响。结果表明,所有制备的Mn-TiO2均表现为锐钛矿相,Mn的掺杂抑制了TiO2晶粒生长,且以MnSO4.H2O为锰源制备的Mn-TiO2粒径略小于以MnC2O4.4H2O为锰源制备的样品,所有Mn-TiO2催化剂的光响应范围拓宽至可见光区域,对罗丹明B具有明显的可见光降解效果,并且以MnSO4.H2O为锰源的催化剂具有较高的光催化活性。     

陶瓷基纳米二氧化钛膜的制备与性能研究

控制钛氧有机物水解条件合成稳定的纳米二氧化钛胶体,X射线衍射和扫描电子显微镜研究表明,该胶体的胶粒为锐钛矿型晶体,晶粒大小约12nm。将制得的纳米二氧化钛胶体喷涂于陶瓷表面,经焙烧处理得到陶瓷基纳米二氧化钛膜。扫描电子显微镜和气相光催化反应实验显示,陶瓷基纳米二氧化钛膜由致密的球形纳米二氧化钛粒子组成,光照下具有好的分解有机物的能力和光诱导亲水性,其光催化分解有机物的反应属于动力学一级反应。此陶瓷材料拥有良好的自洁净功能和光诱导亲水性。     

油溶性纳米二氧化钛的制备及自修复性能研究

摘要：纳米TiO2在润滑行业中应用的瓶颈问题是其在基础油中分散稳定性较差。研究以钛酸四丁酯（TBT）为引发剂,在60℃下引发δ-戊内酯（DVL）开环聚合生成四臂星型聚戊内酯（4-PVL）,然后在酸性条件下水解得到油溶性纳米TiO2。SEM测试结果显示产物纳米TiO2具有大小均一的球形颗粒,其平均直径在20-30 nm左右。通过红外光谱（FT-IR）、X射线粉末衍射法（XRD）、热重分析（TG）等分析测试手段证明了纳米TiO2表面接枝了油溶性聚戊内酯（PVL）,并能够在基础油中保持60天没有发生明显的沉淀现象,展现出良好的分散稳定性。由于球形纳米TiO2的“滚珠”效应和填充修复作用,复合纳米基础油的摩擦系数从0.049下降至0.025,平均磨斑直径从1028 μm 降低至979 μm,展现出良好的抗磨及自修复性能。     

固定式填充复合床光催化反应器降解亚甲基蓝的研究

设计了一种固定式填充复合床光催化反应器,以普通玻璃片和玻璃螺旋圈为载体,用溶胶-凝胶法制备了负载型TiO2薄膜光催化剂。利用紫外光为光源,采用难降解物质亚甲基蓝在不同初始浓度、pH值和光强等因素下的光催化降解脱色反应速率考察了该反应器的工艺特性,试验结果表明:该种反应器的最佳操作条件为反应器中同时放置普通玻璃片TiO2薄膜光催化剂和玻璃螺旋圈TiO2薄膜光催化剂,溶液pH值为7.5,光源光强为650W,光照时间为180min。当进水亚甲基蓝的质量浓度为8.0mg/L时,在此条件下的降解脱色效率为93.83%,且其设计易于实现产业化。